Neuro Flashcards
What drug can be used to confirm a diagnosis of myasthenia gravis?
Edrophonium
ACh esterase Inhibitor
A positive Romberg test indicates a problem in?
Medial lemniscus (dorsal column) - carries proprioception, vibration, light touch Problem with proprioception or vestibular apparatus, sensory deficits
Age related hearing loss is caused by degeneration of?
the proximal hair cells of the organ of Corti
Presbyacusis
harder to hear high pitched voices
A pt with daytime sleepines and decreased sleep time and decreased REM sleep time. Which neurotransmitter is responsible for the decrease in the patient’s REM sleep?
Decreased ACh
ACh induces REM and normal aging is associated with a decrease in ACh.
Older Pt with proximal muscle weakness (difficulty walking up stairs or rising from a chair), delayed relaxation of muscles (slow to unclench a fist), notes that mom had a similar condition
Myotonic dystrophy type 2
nucleotide repeat expansion (CCTG) withing the CNBP gene
Type 1 presents in childhood
What test can be used to confirm a dx of Parkinson?
Clinical response to Dopamine
Microglia are differentiate from which germinal tissue?
Mesoderm. Differentiate from blood monocytes (think of microglia as CNS macrophages)
A pt presents with hoarseness following a thyroidectomy. Which pharyngeal arch is the origin of this nerve?
Branchial arch 6
recurrent laryngeal n. (Branch of X) inn the muscles of the larynx
Following a surgery a pt has difficulty swallowing and absence of gag reflex. Which pharyngeal arch was damaged?
Brnachial arch 4
Superior laryngeal inn paryngeal constrictors, cricothyroid, levator veli palatini
A child presents with a large abdominal mass, HTN, dark circles under the eyes, elevated urine catecholamine. Bx of the mass reveals small round cells with hyperchromatic nuclei forming a pseudorosette pattern around central primative nerve fibers
Neuroblastoma
Most common tumor of the adrenal gland in children
Also most common malignant solid tumor outside of the cranium in children
Caused by amplification of N-myc (protooncogene)
A study that follow subjects without a disease who are then randomized into different levels of exposure to a risk factor and monitored for development of dz is what type of study?
Prospective cohort
Parkinsons dz is caused by degeneration of?
Dopamine producing neurons in the substantia nigra
A pt with a herniated disc at the L5-S1 level will likely have weakness in which reflex?
Compressed S1
Diminished ankle-jerk reflex
A pt with right sided loss of coordination (ataxia), hypotonia, intention tremor, and instability (pt feels like they will fall). Difficulty with finger to nose test on right side. Where is the lesion?
Right cerebellar hemisphere
Cerebellar lesions are ipsilateral
A pt with classic bell palsy where the whole half of his face is paralyzed
Lower moto lesion CN VII
If it was upper motor her would be able to move his eyebrows
During preparation for surgery a pt is confused, tachycardic, tachypneic, and hypertensive. Skin is dry, flushed, warm to the touch with fixed dilated pupils. Pt has been overdosed on?
Atropine
Nonselective muscarining antagonist used in surgery to suppress bronchial secretions
Correct with physostigmine
alpha synuclein deposits is associated with?
Parkinson dz
alpha synuclein = Lewy bodies
A pt presents with uncontrolled DM and diplopia. Right eyelid is drooping and eye is abducted and depressed. Which EOM is still functioning?
Lateral rectus (CN VI) Superior oblique (CN IV) Pt has CN III palsy due to DM neuropathy (inf med and sup rectus, inf oblique)
What is an abortive therapy that is used in a pt with repeat cluster HA?
Oxygen inhalation therapy
Following surgery a pt has lost bilateral motor, pain, and sensation below dermatome T6.
Vibration, light touch, and position sense are intact. What happened?
Hypoperfusion of the anterior spinal a.
Sole vessel that feeds the ventral 2/3 of the spinal cord
artery of adamkiewicz feeds the lower spinal cord (T8-L4)
What is the function of the nodes of Ranvier?
Sites of inward current
Facilitates saltatory conduction
In order to cure Shingles, the drug would have to penetrate the?
Perineurium
This is the tissue that surrounds fascicles of nerve fibers and serves at the permeability barrier in the nervous system
A pt states that his legs violently shakes when he walks and that his dad and uncle had similar symtpoms. On PE the muscles of the leg are held in spasm. Dx and where is the lesion?
Spastic paraplegia AKA hereditary spastic paraplegia
Lesion in the corticospinal tract.
Which tract controls the descending voluntary movements of contralateral limbs?
Lateral corticospinal tract
Legs are Lateral
Symptoms of pancoast/superior pulmonary sulcus tumor
Usually due to non small cell lung cancer in the lung apex
ipsilateral shoulder pain
Horner syndrome (ipsi)
Atrophy of intrinsic hand m. (ipsi)
Upper extremity edema (vascular compression)
DO NOT present with classic lung cancer syx
A neonate presents with a tuft of hair on her back covering a dimple over L5. No neuro defect
Spina bifida occulta
Spina bifida cystica would incl. the meninges and sometimes the spinal cord
The patellar reflex tests which nerves?
L3 and L4
A pt presents with weakness in her left leg ONLY. Occlusion is likely in the?
Right anterior cerebral a.
A pt with organophosphate poisoning should be treated with?
Pralidoxime
Organophosphates are acetylcholinesterase inhibitors and can become irreversible if they aren’t treated quickly. Excessive cholinergic stimulation = DUMBBELSS (Diarrhea, urination, miosis, bronchospasm, bradycardia, excitation of skeletal muscle and CNS, Lacrimation, sweating, salivation)
FGFR is a defect in the maturation of which tissue?
Cartilage
Achondroplasia
AD
A pt that recently started an antipsychotic for suicide attempts is presenting with a head tilt that cannot be straightened without considerable pain. Dx?
Acute dystonic reaction (spasmodic torticollis) due to Dopamine antagonism in the migrostriatal pathway
Extrapyramidal symptom of antipsychotic medications
Action of benzodiazepines
Increase frequency of Cl- channel opening
Action of barbituates
Increase duration of Cl- channel opening
A pt that carries the apolipoprotein E-4 allele is at risk for?
Late onset Alzheimer dementia
What are the genetic risk factors for early onset (
- Amyloid precursor protein (APP on chr 21)
- Presenilin 1 on chr 14
- Presenilin 2 on chr 1
Pentapeptides with affinity for delta and mu receptors
Enkephalins, endorphins, and dynorphins = endogenous opioid peptides
Release in response to pain for pain modulation
Which molecules are made from the precursor polypeptide proopiomelanocortin (POMC)
Beta-endorphins (endogenous opioid peptide)
ACTH
MSH
A 2 day old is presenting with tremors, tachypnea, sneezing, diarrhea. Mom has poorly controlled schizophrenia, Hep C, and received limited prenatal care. Baby has increased tone and quiets when swaddled. Dx?
Neonatal abstinence syndrome due to opiate w/d
Tx - methadone or morphine. Increase dose until syx resolve and then taper the baby off over several weeks
Would you give naloxone to a pt in opiate w/d?
No. This is a pure opiod receptor antagonist and would worsen w/d symptoms. Only use in overdose. Use methadone for w/d
Why do you give a pt cabidopa and levodopa?
Carbidopa inhibits peripheral conversion of levodopa making it more available to the brain
What behavioral changes can be seen in high dose combo of levodopa and carbidopa?
anxiety, agitation, insomnia, confusion, delusions, hallucination
Can try reducing dose or adding an antipsychotic (clozapine)
A neonate is born with underdeveloped mandible and hypoplastic zygomatic bones due to failure of development of the first and second pharyngeal arches. What other structure is probably abn?
Stapes
Treacher-Collins syndrome = genetic disorder causing abn development of first and second pharyngeal arches
Craniofacial abn lead to ariway compromise, feeding difficulties, conductive hearing loss
A pt injured his shoulder and presents with sensory loss over the lateral shoulder and weakness on should abduction
Axillary n. injury
Weakness due to denervation of the deltoid
Pt has shooting pain down the back of her leg. + straight leg test, weak hip extension. Absent ankle jerk reflex. Dx?
Sciatica (L4-S3)
Usually caused by disc herniation
Prenatal valproate use (bipolar, epilepsy) increases the risk of the fetus developing?
Nueral tube defecs
What do inhalation anesthetics, barbiturates and benzos target in order to achieve CNS depression?
Potentiate the inhibitory action of GABA
Other than the desirable CNS effects, what other affects do inhaled anesthetics have on the body?
- Decreased CO (hypotension)
- Respiratory depression (hypercapnia)
- Decreased vascular resistance in the brain (increased cerebral blood flow)
- Decrease GFR
- Decreased hepatic flow
What is the most likely sequelae of untreated congenital hydrocephalus?
Muscle hypertonicity
Congenital hydrocephalus is usually caused by?
Malformation that prevents drainage of CSF (Chiari, Dandy-Walker, infection, hemorrhage
Teenage boy presents with intellectual disability/ADHD, prominent forehead, long and narrow face, prominent mandible, large testes, hyperlaxity of finger and thumb joints
Fragile X syndrome
loss of function mutation in fragile X mental retardation 1 gene (FMR1)
A pt has bilateral visual difficulty that is progressing. Fundoscopy reveals small yellow retinal lesions clustered in the macula. What would you expect on visual field exam?
Central scotomas
scotoma = any visual defect surrounded by a relatively unimpaired field of vision
Dx = Macular degeneration
What is the pathogenesis of macular degeneration?
progressive loss of central vision due to deposition of fatty tissue (drusen) behind the retina (dry MD) and neovascularization of the retina (wet MD)
A pt with a fx on the orbital floor (zygomatic and maxilla) is likely to have injury to which nerve?
Infraorbital n.
May have loss of sensation over the upper lip
A child presents with difficulty walking, frequent respiratory infections, cerebellar atrophy and impaired DNA repair. Dx?
Ataxia - telangiectasia
ar
DNA is hypersensitive to ionizing radiation and increases risk of cancer
Blood solubility of an anesthetic is indicated by its
Blood/gas partition coefficient
High solubility has a higher partition coefficient
A drug that has higher solubility will have a slower rise in partial pressure in the blood, but it will be able to unload in the brain faster.
A pt with contralateral homonymous hemianopia with macular sparing (ie blind in the right half of each visual field) has a occlusion in?
Posterior cerebral a.
Macula is spared due to collateral blood from the middle cerebral a. to the occipital pole
An MS patient will experience a decrease in which neuronal property as a direct result of demylination?
Length constant
AKA space constant
measures how far along an axon a signal can propogate
How do you treat a pt with status epilepticus?
- Lorazepam (benzo) to abort active seizure
- Phenytoin (blocks inward movement of Na+) - for long term management
If seizure continues - give a barb
Pt presents with Left arm clumsiness. On PE - motor weakness of left arm and leg, slurring, drooping of left lower face. Passive extension has initial resistance followed by sudden release of tension (clasp-knife spasticity). Where is the lesion?
Internal capsule
Clasp-knife spasticity suggests UMN lesion due to lack of inhibition. Can affect any portion of pyramidal motor system.
Internal capsule stroke = pure motor weakness affecting contralateral arm, leg, lower face
A pt wants a sleeping pill that isn’t addictive. You recommend
Zolpidem
short acting hypnotic that is unrelated to benzo’s but action is similar (enhance GABA). Short term treatment of insomnia
Eye adduction depends on which nerve?
Occulomotor (CNIII)
A pt with Down’s syndrome that is become increasingly forgetful likely has?
early onset Alzheive
~ 40 y/o
Increased neuronal amyloid precursor protein
Pain sensation from the median sulcus of the tongue anterior to the foramen cecum is carried by?
Mandibular division of trigeminal n. (ant 2/3 of tongue)
Posterior 1/3 of tongue has sensory inn by?
glossopharyngeal (CN IX)
Anterior 2/3 of taste buds are inn by?
Chorda tympani of facial n. (CNVII)
Posterior 1/3 of taste buds are inn by?
Glossopharyngeal n (CN IX)
At autopsy a pt has an atrophic precentral gyrus and thin anterior roots of the spinal cord. On microscopy loss of neurons in the anterior horn of the spinal cord and in the hypoglossal and ambiguous CN nuclei. Corticospinal tracts stain only lightly (demyelinization) dx?
Amyotrophic lateral sclerosis
Combined UMN and LMN lesions
A pt with a pure motor hemiparesis (ie right sided weakness) and a small cavitary lesion in the internal capsule likely has a ?
Lacunar infarct
Caused by Hypertensive arteriolar sclerosis due to chronic HTN
CT is negative acutely but will show the cavitory lesion after a few weaks
In a pt with absence seizures, treat with?
Ethosuximide
Decreases calcium current in thalamic neurons (blocks T-type Ca2+ channels)
Which seizure medications inhibit neuronal firing by reducing Na+ entry?
Phenytoin
Carbamazepine
Valproic acid
Following an appendectomy a pt loses sensation over the suprapubic area but cremaster reflex is intact. Which n. was damaged?
Illiohypogastric
L1
motor function to anterolateral abdominal wall m.
What determines potency of an inhaled anesthetic?
Minimal alveolar concentration
% of anesthetic in the inspired air that renders 50% of patients unresponsive to painful stimuli
Potency = 1/MAC
Does NOT depend on pt height weight or gender
A pt presents with HA’s caused by an expanding neoplasm in the cerebellar hemisphere. What other finding would you expect in this pt?
ipsilateral
- dysdiadochokinesia (impaired rapidly alternating movements)
- limb dysmetria (over or under shoot during targeted movement)
- Intention tremor
Why do DM pts get peripheral neuropathy?
- Non-enzymatic glycosylation of neuron leads to Endoneural arteriole hyalinization and eventual nerve ischemia
- Intercellular hyperglycemia occurs in peripheral nerves = glucose is converted to sorbitol and fructose. Sorbitol increases osmolarity and facilitates water influx in the cell
A middle aged Caucasian woman is unable to walk. Spinal cord shows symmetric myelin layer vacuolization and axonal degeneration of posterior column and lateral corticospinal tracts
Subacture combined degeneration
Vitamin B 12 deficiency causes abn myelin synthesis. Leads to degeneration of:
1. Dorsal column (bilateral loss of position and vibration sense)
2. Lateral corticospinal tracts (UMN signs)
3. Axonal degeneration of peripheral nerves (numbness, parathesia)
Kid with hypoplasia/absence of cerebellar vermis and cystic dilation of 4th ventricle?
Dandy Walker malformation
Present with developmental delay, skull enlargement, unsteadiness, impaired coordination
Can develop non communicating hydrocephalus
A pt with a solitary mass in right temporal is likely to have which visual field defects?
Left homonymous superior quandratanopia
“Pie in the sky”
Upper Left corner lost in both eyes
NOTE contralateral
Neuritic plaques are found in pts with?
Alzheimer’s dz
Neuritic plaque = neurofibrillary tangle
Aggregates of hyperphosphorylated tau protein
A pt has a bilateral hand tremor that improves when she drinks a small amount of alcohol. Dx and Tx?
Dx - Essential tremor, AD
Tx - Propanolol, non selective beta blocker
A kid with Absence seizures that have be refractory to other antieplieptics is given lamotrigine. What side effect should he be warned of?
Stevens - Johnson syndrome (toxic epidermal necrolysis)
What is the MOA for lamotrigine?
Blocks voltage gated Na channels
Use in partial and generalized seizures. Also effective in bipolar
Which anticonvulsants can cause Stevens-Johnson syndrome?
Lamotrigine Carbamazepine phenobarbital Phenytoin If any rash develops, d/c immediately
Epidural hematoma is caused by rupture of?
Middle meningeal artery
lucid interval
Lens shape
Trauma, skull fx
Subdural hematoma is caused by rupture of?
Briding veins
Gradual headache with a slow decline in mental function
Crescent shape
Elderly pt prone to falls
Pt has a large left lung mass on CXR and presents with shoulder pain, persistant hiccups, dyspnea, decreased breath sounds on L side. Which nerve is being compressed?
Phrenic n. (C3-C5)
inn ipsi hemidiaphragm (decreased breath sounds on L)
Referred shoulder pain = C3
From top to bottom, what is the order of the nerves leaving the brachial plexus?
Musculocutaneous n. Axillary n. Radial n. Median n. Ulnar n.
Damage to the radial n. would result in?
Wrist drop
Unable to extend wrist
Weakness in wrist flexion is due to damage in which nerve?
Median or ulnar
A pt undergoing rotator cuff surgery is given an injection of anesthesia between the right anterior and middle scalene to block the brachial plexus. Which other muscle is likely to be paralyzed?
Diaphragm
Brachial plexus = C5-T1
Phrenic n. = C3-C5
Avoid interscalene block in pts with lung dz or contralateral phrenic n. dysfunction
A pt with diplopia and new hand/foot clumsiness likely has depletion of which cell type?
Oligodendrocytes
Dx = MS
Communicating hydrocephalus is caused by a defect in?
Arachnoid granulations NO obstruction in CSF flow Usually a sequelae of meningitis or hemorrhage All ventricles symmetrically enlarged Wet Wacky Wobly
What is the pathway of CSF flow through the ventricles?
Choroid plexus secretes CSF into lateral and 4th ventricle
Lateral ventricle -> interventricular foramen of Monro -> 3rd ventricle -> Cerebral aqueduct -> 4th ventricle -> foramina of Luschka and Magendie -> subarachnoid space -> absorbed by arachnoid granulations -> venous sinuses
Non communicating hydrocephalus is a defect in?
Normal flow of CSF
Only ventricles above the obstruction will be dilated.
Congenital anomalies - Dandy-Walker, Chiari, aqueductal stenosis
A pt with vision loss on one side likely due to a lesion?
contralateral optic tract
Optic tract comes after the optic chiasm
Will also have a defect in pupillary light reflex in the contralateral eye
Which nerves would be affects in Jugular foramen (Vernet) syndrome?
CN IX, X, XI
IX - loss of taste in post 1/3 of tongue,
IX, X - loss of gag, dysphagia
X - Dysphonia, hoarseness, uvula deviates away from lesion
XI - SCD, trapezius m. paresis
An anesthetic has a very large arteriovenous concentration gradient after beginning inhalation
Slow onset of action
Onset of anesthesia depends on when sufficient quantity of anesthetic is transferred to the brain.
A pt presents with parathesia over their thumb and first two fingers
Carpal tunnel syndrome (CTS)
Compression of median n., often bilateral
Assoc with pregnancy, hypothyroidism, DM, RA, amyloid (decreases carpal tunnel space)
Pt presents with a HA and a right pupil that is dilated and non reactive to light and accomodation, vertical and horizontal diplopia. Right eye is down and out with ipsilateral ptosis. Dx?
CN III exits midbrain between posterior cerebral and superior cerebellar a. - and aneurysm in either artery can cause a non-pupil sparing CNIII palsy
If the pupil was spared, more likely that the syx would be due to ischemia
A pt with stabbing pain in the extremities and stumbling at night tests positive for VDRL. Where is the degeneration in the spinal cord?
Tabes dorsalis (neurosyphilis)
Damage to sensory n. in dorsal roots leading to demyelination and loss of axons in the dorsal column of the spinal cord.
Pain, parathesia, and loss of virbratory and position sense.
Expect Argyll Robertson pupils and + Romberg on PE
Following delivery a woman presents with urinary incontinence and mild preineal pain. DTR or 2+ with normal tone. Cause?
Pudendal n. injury (S2-S4)
Reenters the pelvis near the ischial spine (prone to stretch injury)
Inn pelvic floor, external urethral and anal sphincters
21 year old presents with HA, dizziness, and gait imbalance. HA are over occipital region and MRI reveals low-lying cerebellar tonsils. Dx?
Chiari malformation type I (congenital)
Cerebellar tonsils herniate through foramen magnum
e)
What is unique about Chiari malformation type II?
type I - benign, presents in teen/young adult as HA and dizziness
Type II - neonate, non communicating hydrocephalus (aqueductal stenosis), dysphagia, strido, apnea
50 year old man presents with loss of inhibition, irritability, and personality change. Dx?
Frontotemporal dementia (Pick's dz) Atrophy of frontal and temporal lobes
What are pick bodies made of?
cytoplasmic inclusions of microtubule associated protein tau
Initial syx = personality change (apathy, socially inappropriate behavior)
Teenage girls presents with gait instability. Progressive clumsiness, Kyphoscoliosis, pes cavus, bilateral lower extremity ataxia. Position and vibration sense impaired. Dx?
Friedreich ataxia
ar, lateral corticospinal tract involvement
At risk of developing hypertrophic cardiomyopathy (most common COD)
Which medication induce CYP450?
Phenytoin Rifampin Barbiturates Carbamazepine Griseofulvin Alcohol
Which medications inhibit CYP450?
Isoniazid Cimedtidine Macrolides Azoles Grapefruit juice
A 78 y/o right handed man has a PMH of two TIA’s and HTN. He is presenting with inability to recognize people visually. What visual disturbance is likely?
Loss of upper left corner in both eyes
Prosopagnosia (inability to recognize faces) suggest right inferior temporal lobe, specficially the right fusiform gyrus. This is fed my the middle cerebral a. Presents with crontralateral superior visual field quadrant loss
Contralateral b/c it is behind the optic chiasm
What CT findings may be seen in a pt with Myasthenia gravis?
anterior mediastinal mass due to thymic abnormalities (thymoma, thymic hyperplasia)